Vintage Stereo Repairs - Need Replacement Parts

[lti]

I have two old stereo systems that I am trying to repair.

The first is a Fisher MC-4550. It works perfectly, except that the left channel keeps cutting out. I found that sound will play from both channels if I turn the function switch back and forth a few times, but the sound will start cutting out again after about half a second. I can't seem to find the strange selector switch that I need.

The second stereo is a Zenith Allegro. The belt is broken in the 8-track player, the power switch is broken, and the speaker selector switch is dirty. If I can't clean this switch, I will need a replacement for it as well. I can also hear a 120Hz hum coming from the amplifier.

Also, I need a service manual for both stereos so I know how to get them apart and how to replace the belts.

[smason]

Re: Vintage Stereo Repairs - Need Replacement Parts

On the Fisher, can you not clean the switch?
I wish I had 5 dollars for every stereo receiver I fixed by cleaning speaker or function switches in the 80s.

[lti]

Re: Vintage Stereo Repairs - Need Replacement Parts

I don't see any way of cleaning it. It has a metal enclosure around it that does not have any openings I can spray contact cleaner in.

[Th3_uN1Qu3]

Re: Vintage Stereo Repairs - Need Replacement Parts

The metal enclosure can usually be removed. I'm quite sure you won't be able to find a replacement switch so try your best to take it apart in a way that you'll still be able to put it back together.

[lti]

Re: Vintage Stereo Repairs - Need Replacement Parts

That might work, but I can't figure out how to remove the board.

[Krankshaft]

Re: Vintage Stereo Repairs - Need Replacement Parts

If you're talking about a volume pot most if not all have a direct shot to the wafer and contacts around where the contact pins connect to the wafer. Make sure the holes are facing up and put the little hose on the nozzle and shoot it in gravity will do the rest. Work the pot back and forth to spread the cleaner.

Deoxit is a great cleaner for volume pots and other contacts it's expensive but a little goes a long way.

I've revived 1950s tube radio pots that were scratchy and hard to turn and made them turn smoothly and work as good as new so I'm sold on the stuff.

[lti]

Re: Vintage Stereo Repairs - Need Replacement Parts

It is a selector switch that I need to clean/replace. I would rather replace the switch than try to take the metal cover off. I also do not know how to take this stereo apart. I will need the service manual for it.

[cadiman]

Re: Vintage Stereo Repairs - Need Replacement Parts

I have never taken these apart to clean them either.
It won`t take much.
My parents have an SX-780 pioneer and I always clean all the pots and switches every year do to channel drop out or static.

[lti]

Re: Vintage Stereo Repairs - Need Replacement Parts

If you have to clean the pots and switches that often, it might be time for new ones.

I haven't done anything to either of these stereos yet. I would like to find a replacement function switch for the Fisher and a power switch and replacement belts for the Zenith.

[999999999]

Re: Vintage Stereo Repairs - Need Replacement Parts

It might help if people know what they were exactly. Pull them out, or at least free of the front panel and post pictures and dimensions. There are things you can do to improve some switches. For example, taking apart a switch and wetting the contacts with silver solder will mean you no longer have brass oxidation. Silver oxidation still conducts. Naturally, gold plated switches would be best but good luck finding some when you can't find plain ones.

If you want to find a replacement switch anyway it won't hurt to tear open the old one since it is otherwise useless. I too have cleaned contacts in old switches many times, after I get it open I use brasso not just contact cleaner, or if they are really bad, an abrasive ink pen eraser (more grit in it than a pencil eraser so it works faster) then brasso to polish them. Depends on the switch though, what the best option is.

[lti]

Re: Vintage Stereo Repairs - Need Replacement Parts

I can't figure out how to get the Fisher apart. I don't want to take the original switch apart because I don't want to completely destroy it. The switch works properly most of the time. I haven't tried to work on the Zenith yet. I have attached a crappy picture of the switch. The switch is soldered directly to the board and has six positions.